The field of the invention relates to devices for piercing the wall of a fluid containing member such as a pipe or conduit in order to place the interior of the fluid carrying member in fluid communication with another container or conduit.
Prior art devices for accomplishing this general objective are illustrated in U.S. patents such as Ehrens, U.S. Pat. No. 3,554,217; Cole, U.S. Pat. No. 3,896,842; and McMurray et al, U.S. Pat. No. 3,287,997. In such prior art devices it has been customary to fasten the piercing or tapping means to the exterior wall of a pipe with suitable sealing means. In operating such devices it is typical to employ a rotary screw threaded tapping means having an end configuration either to pierce or puncture the wall of the container vessel or for rotary cutting of a slug from the wall of the conduit. In all such instances a rotating sharp ended tool member does the gradual cutting or piercing through the wall thickness of the conduit.